Few people care about that. But, most software is written in teams. For comparison, imagine a book written by many authors. Everyone can edit everything. You sure would like to have a way to restore and get back previous versions. If something stops making sense, you would want to know who changed what when. You can imagine the whole process has lots of social "dynamics". So the software you use to version computer files has quite some impact on the way people work together and how software is build. Now the funny thing is, in most cases the software used is actually an ancient piece and the world hasn't settled yet on a new system. And also, it is actually a difficult problem to understand and also technically quite challenging to address.

So enter Linus Torwalds, as he had the same basic problem (or pleasure) as every other programmer out there. How to work together with other programmers.